Purchase of a NanoTemper Monolith NT.115 from NanoTemper Technologies is proposed. Microscale Thermophoresis (MST) is a relatively new technology that due to extreme ease of use and measurement quality is rapidly becoming a preferred method to determine affinities. MST measures binding affinities by measuring the motion of molecules along temperature gradients within glass capillaries and detecting changes in their hydration shell, charge, or size that occur during a binding event. MST is a solution technique that does not require immobilization of the binding partners. Hence, interactions between a wide array of biological molecules (e.g. proteins, nucleic acids, lipids, carbohydrates, cofactors, small molecules) can be studied. The new state-of-the-art MST instrument will be placed in a core facility operated by the Center for Structural Biology (CSB). The MST instrument brings new technology that is faster, more sensitive, and requires one fifth as much sample as low volume ITC. Thus, the new instrument will increase productivity of the six Major and six Minor Users of this proposal and help attract additional users whose research programs can benefit from the quantitative insights into binding phenomena provided by MST. The availability of an easy to use, low volume, inexpensive to operate MST instrument in a core facility, combined with well-established mechanisms that advertise the resource and provide outreach to interested scientists will have a broad impact on basic and translational research at Vanderbilt. Funding of this instrument will directly enhance NIH-sponsored projects at our institution in a variety of areas, including Biochemistry, Chemistry, Chemical Biology, Immunology, Microbiology, Molecular Toxicology, Pharmacology, and Structural Biology. Since MST is simpler and technically more forgiving, we anticipate that the new instrument will enable use of MST in exciting new research areas such as chemical probe development and preclinical drug discovery. A critical role in drug discovery has already been identified in that Professor Fesik's (Major User #5) has reached a discovery limit because his current fluorescence polarization based assay fails when his new ligands exceed the affinity of fluorescent probe peptides.